溫度與缺水效應對史丹吉氏小雨蛙蝌蚪存活與發育之影響

Effects of Temperature and Water Deprivation on Survival and Development of Microhylid Frog (Micryletta steinegeri) Tadpoles

史丹吉氏小雨蛙爲爆發性生殖者，其產卵棲所選擇在暫時性的水域環境，孵化後的蝌蚪則在此靜止水體中活動。本研究選擇了溫度及水分因子，來進行影響該蛙蝌蚪存活與發育的試驗。結果顯示該種蝌蚪在缺少積水的環境下，無法存活超過1小時，爲本實驗所檢視的狹口蛙類及其他共同生活在此暫時性水域的無尾目蝌蚪中，最無法忍受無積水環境的物種。在20℃與25℃的溫度下，最適合該蛙蝌蚪的成長與發育，其平均變態率可達38%；在25℃與30℃的環境下，最短的蝌蚪發育期僅需11天；在15℃的低溫下，蝌蚪於長出後肢後，成長即趨緩，發育也呈現停滯，因爲無法伸出前肢，因此也無任何個體可達Gosner第42期之變態高峰。本文也比較不同環境下的蝌蚪發育日數，並探討環境因子對該蛙蝌蚪期長短的影響。

The mycrohylid frog Micryletta steinegeri is an explosive breeder whose tadpoles live in still waters in the temporal zone. In this study we investigated the effects of temperature and water deprivation on survival and development of the tadpoles. The results showed that the tadpoles could not survive for an hour at 25℃ without water. They had the lowest tolerance to water deprivation among the members of Microhylidae examined and of other anuran tadpoles coexisting in the temporary waters. The optimal temperatures for the growth and development of the mycrohylid tadpoles with a mean metamorphic rate at 38% were at 20℃ and 25℃. The shortest tadpole period was 11 days at 25℃ and 30℃. At 15℃ the growth decelerated and the development ceased at the stage with protruded hind legs; no tadpole stretched out fore legs to reach the metamorphic climax of Gosner's stage 42. Developmental periods of the tadpoles under different environments were compared, and the effects of environmental factors were discussed.